Switch for electric meters.



PATENTED DEC. 31, 1907.

J. J. WOOD. SWITGH FOR ELECTRIC METERS.

APPLICATION FILED SEPT. 19. 1905.

INVENTOR;

WITNESSES:

7 mm W 0 co WASHINGTON, 12,6.

rinrr JAMES J. WOOD, OF FORT WAYNE, INDIANA.

SWITCH FOR ELECTRIC METERS.

Specification of Letters Patent.

Patented Dec. 31, 1907.

Application filed September 19, 1905. Serial No. 279.140.

To all whom it may concern:

Be it known that I, JAMES J. W001), a citizen of the United States, residing at. Fort Wayne, in the county of Allen and State of Indiana, have invented certain new and useful Improvements in Switches for Electric Meters, &c., of which the following is aspecification.

This invention provides an improved construction of electric switch peculiarly adapted for use with prepayment electric meters, although applicable to other uses.

In my application Serial No. 257 ,838, filed April 28, 1905, I have set forth a construction of electric switch which is the precursor of my present invention.

My invention provides certain improvements applicable particularly to cam-operated switches, such as that set forth. in my said application.

In the accompanying drawingsFigure 1 is a front view of the switch and its operating mechanism, partly broken away in vertical section, showing the switch open. Fig. 2 is a front view of the switch and a fragment of the operating cam, showing the switch closed. Fig. 3 is a fragmentary view, showing the operation of uncatching or tripping the switch. Fig. 4 is a plan of the operating lever. Fig. 5 is an elevation of the catch detached. Fig. 6 is a fragmentary view of the contact springs or bridge, 011 a larger scale.

Let A A and B B represent contact terminals, which are preferably constructed to serve also as binding posts, in which are confined the ends of the circuit wires 1, 2, 3 and 4. The respective contact terminals, when the switch is closed, are connected by conducting bridges C and C. These conducting bridges are carried 011 a cross-bar or yoke D, which is connected by a rod E to an operat ing lever H projecting from a fixed hub or shaft I, and from which projects upwardly an arm J carrying preferably a roller a which is engaged by a cam notch 1) formed in the cylindrical surface 0 of a wheel or disk K. The rod E slides in a guiding post F and carries a spring L for pressing down the cross bar D to open the switch, and a stiffer spring M for pressing on this cross-bar when the switch is closed. The conducting bridges C C are formed as metallic brushes, making end contact with the respective terminals. Each bridge consists of several leaves or laminae of resilient sheet-metal fastened at their middles to a stirrup piece 6 and having their ends upturned. They are partially flattened out during the closing movement, so that their edges rub against the contact pieces and keep the contacting surfaces clean and bright. The outer lamina g is prolonged so that in the closing movement it touches the terminals in advance of the other, and in the opening movement is the last to break contact with the terminals, so that the resulting spark affects only this out-er lamina and cannot corrode the contacting surfaces of the main portion of the bridge.

So far as described, the construction is the same as that set forth in my aforesaid application, and upon which my present invention is based. The present invention however is not limited to the constructional features of the switch thus far described, which may be varied in the discretion of those skilled in the art or substituted by any other known or suitable switch constructions.

In a switch of the general character set forth, where the opening and closing movements of the switch are derived from a cam, the speed. with which the switch contacts move depends upon the speed of movement of the cam. In the closin movement, the cam, turning from its initia position, shown in Fig. 1, in the direction of the arrow, first eXpels the roller from the notch b until it rides upon the peripheral surface 0, thereby forcing the switch to the closed position shown in Fig. 2, upon the return or backward movement of the disk the roller finally drops back into the notch I), with a speed which cannot exceed that permitted by the movement of the cam, thereby opening the switch with a speed which in some instances is not sufliciently rapid to prevent undesirable sparking or arcing. It is desirable in all instances that the switch shall open with a very quick and rapid movement, in order to minimize the tendency-to arc. This resuit is accomplished according to my present invention by providing the switch with a spring catch, which, when the switch is closed, acts toretain it in that position, and which, upon the completion of the final movement of the cam, is tripped to release the switch and permit the latter to fly open with a speed limited only by the stiffness of its operating spring.

In applying my present invention to the construction of switch already set forth, I preferably provide a dog or catch lever P shown separately in Fig. 5 which is pivoted at p to the operating lever, preferably to the arm J, and has two arms, one of which terminates in a hook q ada ted to engage a fixed shoulder which may be formed on a in 0", while the other arm of the catch terminates at s in a face suitably shaped for engagement by a tripping pin or projection t carried by the cam. A spring u presses the catch in such direction as to cause its hook q to engage the pin 1" and press back against it so as to hook over this pin, as shown in Fig. 2, and thereby hold the operating lever in the position it occupies when the switch is closed. The pin t is so arranged that upon the completion of the final movement of the cam, it

strikes the end 8 of the catch and forces it back, as shown in Fig. 3, until the hook disengages itself from the pin, whereupon the switch is thrown open, so that the parts assume the position shown in Fig .1. Thus the movement of the switch, instead of accompanying the final movement of the cam, and being retarded thereby, is deferred until the end of this movement, and is performed much more quickly, so that the switch opens in the manner of the so-called snap-switches.

In a prepayment electric meter the disk K is the indicator on which the prepaid credits are counted up and down, and the extreme movement of which is confined to one revolution. The pin t is so located that when the disk has moved to the end of its revolution, the pin just falls short of colliding with the roller a. It is shown one step short of this position in Fig. 2.

While the details of construction are im material, the catch P is preferably made to work in a fork in the arm J, being a prolongation of the slot in which the roller a is mounted, with its longer arm partly encircling the roller, andits spring a fixed in the catch and pressing against the forked arm.

Instead of having the outer or circuitbreaking lamina 9 make direct and contact with the contact pieces as heretofore, I fasten on the ends of this outer lamina solid contact pieces 9 9 (Fig. 6). These pieces 9 are best made in cylindrical form, and may be constructed of wire cut into short lengths and slotted endwise, the ends of the spring or lamina 9 being inserted and soldered into the slots. These pieces 9 afford a sufficient mass of metal to receive the final spark and prevent injury to the lamina g by burning or corrosion.

My invention may be variously modified in structural features, as will be apparent to those skilled in the art.

I claim as my inventi0n:

1. The combination of a switch tending to open, a cam for closing itby a forward movement, a catch for holding it closed, and means in connection with said cam adapted, upon the backward movement of the cam to its starting point, to trip said catch.

2. The combination of a switch tending to open, a lever arm connected thereto, a cam having a recess 1) and peripheral surface a for enga ing said arm, a catch applied to said arm for holding the switch closed, and means in connection with said cam for tripping said catch.

3. The combination of a switch tending to open, a lever arm J connected thereto, a cam having a recess and peripheral surface 0 for engaging said arm, a catch P carried by said arm, and a projection t for tripping said catch.

In witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

JAMES J. WOOD.

Witnesses:

DOMINGO A. USINA, THEODORE T. SNELL. 

